What Is Constant Quality for Video?

If you are a video enthusiast or a content creator, you might often come across the term “constant quality” while exporting your videos. But what exactly is constant quality, and how does it affect your video’s final output? Let’s explore this concept in detail.

What Is Constant Quality?

Constant quality is a video encoding method that ensures that the visual quality of your video remains consistent throughout the entire duration of the video. In other words, it allows you to maintain a specific level of visual fidelity for your videos, regardless of how long they are.

When you encode a video using constant quality, the encoder will use a variable bitrate (VBR) encoding method to ensure that every frame of your video is encoded with enough data to maintain its visual quality. This means that if there are complex scenes in your video with lots of movement and details, the encoder will allocate more data to those frames to maintain their fidelity.

On the other hand, if there are simpler scenes with less movement and details, the encoder will allocate less data to those frames since they require fewer bits to maintain their visual quality. This ensures that every frame in your video is encoded with just enough data to maintain its fidelity without wasting any additional bits on frames that don’t require them.

Why Is Constant Quality Important?

The main advantage of using constant quality is that it allows you to create high-quality videos without having to worry about their file size or bitrate. Since constant quality uses VBR encoding, it can help reduce the overall file size of your videos while maintaining their visual fidelity.

This means that you can create longer videos without having to compromise on their visual quality or worry about exceeding file size limits. Additionally, constant quality also ensures that your videos are compatible with a wide range of devices and platforms since they use standard encoding methods.

How To Use Constant Quality?

Most video editing software and encoding tools support constant quality encoding. To use constant quality, you need to select the Constant Quality (CQ) or Quality-Based Variable Bitrate (QVBR) option in your encoder’s settings.

Once you select this option, you need to set a specific quality level for your video. The quality level is usually expressed in terms of a CRF (Constant Rate Factor) value, which ranges from 0 to 51. Lower CRF values indicate better visual quality but larger file sizes, while higher CRF values indicate lower visual quality but smaller file sizes.

For most videos, a CRF value between 18 to 28 is considered optimal since it provides a good balance between visual quality and file size. However, the ideal CRF value may vary depending on the type of video you are creating and your specific requirements.


In conclusion, constant quality is an essential concept for anyone who creates or works with videos. It allows you to maintain a specific level of visual fidelity for your videos while keeping their file size under control. By using constant quality encoding methods and setting the appropriate CRF values, you can create high-quality videos that are compatible with a wide range of devices and platforms.